ABSOLUTE MEASUREMENT OF GAS CONCENTRATIONS AND SATURATION BEHAVIOR IN PULSED PHOTOACOUSTICS

Abstract Absolute photoacoustic measurements of the signal strength yielding the concentration and absorption coefficient of ethylene were performed in the IR on the weakly and strongly absorbed 10P 10 and 10P 14 lines of a pulsed CO 2 laser, respectively, using an optimized cylindrical acoustic resonator with Q ∼1000. The calculated photoacoustic signal strength agreed with the measured signal within an experimental error of 10%. With the 157 nm radiation of an F 2 laser pulsed photoacoustics was extended into the VUV region where photodissociation of C 2 H 4 occurs. Optical saturation phenomena were observed for pulsed CO 2 laser and F 2 laser excitation below 3 mJ pulse energy.